I need some help with a certain part I've bought on a trip to electronic part shops alongside plenty resistors and capacitors.
I asked if they had LDRs and they showed me a small drawer on the shelf with LDRs in them, however they all had 3 pins on them. I'm not exactly sure how to use this variation of an LDR / identify the difference in between this and a regular LDR, could you please help me?
The LDR is black coloured and has three pins.
The top of the LDR seems to have two of the patterns found on a regular 2 pin LDR, except they are vertical and connected to each other like two coiled snakes facing each other
Looks like 2 LDR's in series with the middle connection also brought out. So just use the outer two pins and ignor the middle. Indeed a Ohm meter should confirm.
septillion:
Looks like 2 LDR's in series with the middle connection also brought out.
If that's what it is, and I thought the same, I wonder why? I suppose it could be used as 2 independent reads in the same lighting? Middle to 5V, resistor to ground from each outer pin, and each outer pin its own analog pin.
They use them to center a spot of light. You adjust the position until the light falls evenly between the two LDRs and so each one gives the same reading.
Grumpy_Mike:
They use them to center a spot of light. You adjust the position until the light falls evenly between the two LDRs and so each one gives the same reading.
